The present disclosure relates generally to methods for converting inorganic carbon as a solid mineral (such as, but not limited to, carbonates), aqueous species (such as, but not limited to, bicarbonate) or gas (such as, but not limited to, carbon dioxide (CO2))—from energy generation facilities into a biofuel and a bioproduct. More particularly, the present disclosure relates to methods for producing methane and isoprene using Archaea. In one particularly suitable embodiment, the methods of the present disclosure can be used for wastewater management.
Carbon capture and utilization strategies (CCUS) are critical to minimize emissions or remove anthropogenic CO2 from the atmosphere. Yet, green technologies converting CO2 to value-added products in addition to biofuels is lagging.
To date, 30-40% of emitted CO2 results from coal fired power plants and technologies have been developed to remove CO2 from emissions. Additionally, wastewater treatment, such as in municipal, agricultural and industrial waste treatment has gained popularity. Particularly, the demand for water and wastewater treatment products in the top 40 national markets was 47.7 billion in 2012. This total market is expected to reach nearly $53.1 billion in 2013, $59.2 billion in 2014 and about $96.3 billion by 2019, with a compound annual growth rate of 10.2% for the period of 2014 to 2019.
One of the technologies for CO2 removal is the production of carbonate minerals such as calcium carbonate. Further, early microbial wastewater treatment typically involves the breaking down of complex organic matter by microbes, which results in the formation of acetate, formate, methanol, methylamines, H2 and CO2. These compounds accumulate to inhibitory levels in the anaerobic digester if not converted into CH4. Methane-producing microbial species in pure culture and in multi-organism microbial consortia are naturally capable of using anthropogenic carbonates or CO2 for production of isoprene, which they incorporate into branched alkane lipids that constitute cell membranes. Methanosarcinales methanogens are the most metabolically diverse methanogens and can grow efficiently on most methanogenic substrates and/or methane gas (CH4).
It would be advantageous if engineered methanogens could be introduced to the anaerobic digesters to augment the existing population of “wild” methanogens. Additionally, metagenomics analysis of the microbial community already present in the desired wastewater treatment would allow for selection, cultivation, and engineering of dominant strains, which feed on wastewater products to maximize methane and isoprene production.